The present invention relates to a curtain airbag (which is also called an inflatable curtain), an extendable curtain, an airbag for protecting a head, and more specifically, it relates to a curtain airbag being extendable along the side of a vehicle occupant, especially along a upper body including the head.
An example of a conventional curtain airbag (Japanese Unexamined Patent Application Publication No. 2000-79864) is described with reference to FIGS. 4(a)–4(c) and 5 as follows.
In order to protect a head of a vehicle occupant at a side-on collision or rolling of an automobile, a curtain airbag body 1 is attached to a roof side rail 2 of the automobile. The curtain airbag body 1 is formed to have a bag like shape by overlapping two sheets of cloth so as to suture them together with sewing thread.
At the top of the curtain airbag body 1, there is provided an auriform affixing portion 3 projectingly arranged upwardly, and the affixing portion 3 is provided with a bolt insertion hole 4.
The curtain airbag body 1 is folded to have an elongated bar-shape called as a folded formation 1F. The folded formation 1F is banded together with an H-shaped sheet 5. The sheet 5 is made of paper, synthetic-resin impregnated paper, a synthetic resin sheet. The sheet 5 comprises looping portions 6 and 6 looping around the folded formation 1F, a tying portion 7 connecting between the looping portions 6 and 6, a protruded piece 8 projectingly arranged from the tying portion 7, and a bolt insertion hole 9 formed on the protruded piece 8.
In a state that the protruded piece 8 is overlapped on the affixing portion 3 and the bolt insertion holes 4 and 9 are in agreement with each other, the looping portions 6 are looped around the folded formation 1F as indicated by arrows A of FIG. 4(c) and ends of the looping portion 6 are bonded together with adhesive tape or an adhesive.
By looping the sheet 5 around the folded formation 1F in such a manner, toughness is produced in the folded formation 1F. Therefore, the folded formation 1F of the curtain airbag body 1 can be simply attached to the roof side rail 2 by a worker or a working robot who grasps a portion looped with the sheet 5 to adjust the bolt insertion holes 4 and 9 to female-screw holes of the roof side rail 2 and to screw bolts 18 into the female-screw holes through the bolt insertion holes 4 and 9.
As shown in FIG. 5, the respective affixing portions 3 arranged in the curtain airbag body 1 are fixed to the roof side rail 2 with the bolts 18. At the rear end of the curtain airbag body 1, an inflator 10 is inserted. The inflator 10 and the rear end of the curtain airbag body 1 are fixed to a C pillar 13 with a bracket 11 and bolts 12. Numeral 14 denotes a B pillar; numeral 15 denotes an A pillar.
When the inflator 10 is operated to supply gas into the curtain airbag body 1, the looping portion 6 is peeled off the adhesive interface, so that the curtain airbag body 1 is inflated along a vehicle door as shown by a phantom line 1′ of FIG. 5 and is extended on the side of a head of a vehicle occupant like a curtain.
The curtain airbag body 1 is arranged along from the A pillar 15 to the C pillar 13; the curtain airbag body 1 may be arranged only between the A pillar and the B pillar, and between the B pillar and the C pillar.
As described above, the curtain airbag body 1 is substantially in an exposed state and it may possibly be worn during transportation or by being ground with vehicle body members such as a roof garnish after being attached to the vehicle body, so that a material sufficiently resistant to the abrasion has to be selected for the curtain airbag body 1.
Then, the curtain airbag body 1 may be covered with a cover, which is to be cleaved when the curtain airbag body 1 is inflated.
However, if the curtain airbag body 1 is covered in such a manner, the folded and accommodated state of the curtain airbag body 1 cannot be directly observed visually, so that the confirmation of such a state has to be relied on by indirect observing means such as confirmation by touching with a hand, reducing working efficiency.